His room
by I'm Nova
Summary: For letswriteSherlock challenge 6. After a case in Cardiff, Sherlock's worst fear might just become true...or is it something even worse? Crossover with Torchwood later but you can enjoy this without knowing it. And yeah, this is supposed to be horror because of the challenge but I can't write it for the life of me, so only a bit horror later (hopefully). Hurt/little comfort too
1. Chapter 1

_Disclaimer: Nothing is mine. Everything belongs to the evil syndicate Moffatt/Gatiss/RTD (you'll see) and/or to Arthur Conan Doyle, who is innocent because he's dead._

_A.N. The fic title is a reference made plain in the prologue, but if you missed that Dr. Who episode (The god complex) go watch it! It's great! _

His room

Prologue

It's a few months after the end of Hiatus (the word is neutral enough to be acceptable to them both), and their life is back on track. They've just ended case in Cardiff – barely a 6.5, but it looked better – and now they're home and settled for the Dr. Who rerun.

It's the episode where the Doctor and his companions get stranded in a fake 1950s motel where everyone has a room containing his or her worst fear, to lead people to prayer...because faith gets them eaten by the alien of the week.

"I'd be a goner in a second; believing pulled me out of my room once already," John comments softly. He wouldn't normally confess things like this. It just sort of slips out. He doesn't want to let it linger, and since he's admitted his fear (ok, not explicitly, but there's no need to) it's fine to ask, right? So he adds hastily, "And in your room, Sherlock? What would be in there?".

"My father," his friend replies quietly, firmly looking at the screen – not John.

"Come on, with all you've seen, he can't be that bad...Was he?"

The doctor corrects his joking tone abruptly; he still knows next to nothing about Sherlock's family after all. But Mycroft that is, which isn't all that heartening. The older Holmes is still a million miles away from abusive, mind you. Shrugging off his friend's admission is an idiotic move regardless, if John wants Sherlock to confide in him. To give up the secrets he still guards.

"My father was the best man I've ever known. Nonetheless, he's sitting in my room – or he'd be if such a whimsical place existed," the sleuth reiterates, his mask perfect, so that even with the uncomfortable topic he's apparently unaffected. Strangely, he didn't claim he'd have no room because he has no faith in anyone or anything beyond himself. Then again, if Sherlock believes someone will save him from anything, even despite himself, it's probably Mycroft he's thinking about. He qualifies as 'higher power' fairly well.

"You're not going to elaborate on that, are you?" John queries. He doesn't want to make Sherlock feel like he's trying to pry, but neither wants to be told someday, "You never asked," if this comes back to haunt them. It looks like a good compromise.

"Obviously," the detective replies with a shrug.

_Of course_, John thinks. _What was I expecting?_


	2. Chapter 2

_Disclaimer: nothing you recognize is mine. Obviously._

Chapter 1

When after such a conversation he develops a persistent, pulsing, annoying (if not severe) headache, a lesser man than Sherlock would think he jinxed himself. Instead he just goes to sleep. After all, it's just after a case and he deserves it.

The following day, his worry isn't better, but he ignores it steadily. He's decided it might be a consequence of opening that specific bolted room on his mind palace (John doesn't have monopoly on psychosomatic ailments) and the best thing to do is busying himself with something – anything. Now, if only he had anything to do...John's patience is sorely tried that day, but being bearable is the last of the detective's concerns.

By night, Sherlock is frayed enough that he pilfers a paracetamol from his flatmate, even with little faith in its effectiveness. Since sleeping did nothing for his head, he doesn't. Better to be as normal as he can. He takes up the violin instead, choosing a soothing melody. He doesn't want to purposefully irritate anyone, so he might as well play something likely to merge seamlessly into people's dreams. At 3:24 am, though, a jarring note disturbs the darkness. He made an honest mistake. It doesn't happen since he was 13. By the look Sherlock gives his beloved instrument, you'd think he's just been bitten by it. Gently still – that's too ingrained in him by now – he puts it back.

He doesn't appear at all after that, and at lunch John knocks and then quietly allows himself in, when no answer comes. The doctor finds his friend on the bed, curled into the tightest, littlest ball of misery he's ever seen an adult man (never mind one as tall as Sherlock) achieve.

"Sherlock? What's wrong now?" he asks softly.

Nothing suggests he's been heard.

"Either you answer me or I'm bringing you a plate of something. Of my choice," the doctor says, wondering quietly how food between them is used as a threat instead of a bribe.

"I missed a note," his friend grinds out finally.

"That's it?" John replies, because it seems...excessive. Even for Sherlock.

"You don't understand, John!" the detective yells, uncurling to throw himself towards the doctor. Sherlock's right, of course. "I don't remember the whole musical score of the arrangement for violin of Chopin's nocturne n. 20, short as it is. _And I didn't delete it_." He whispers, now, eyes wide with undeniable fear.

"Sherlock, calm down now. Stress doesn't help you to remember anything. It could be a momentary problem. You know, like normal human beings happen to have," John prompts, voice quiet and – hopefully – relaxing. Really, that's ridiculous.

"I've the palace in place not to incur in these _normal humans_' occurrences, John! I can't allow to have them!" the detective growls, glaring harshly.

"Though luck, because _you're human_, Sherlock. Thankfully," the doctor states in his best no-nonsense tone.

You don't know, John!" the sleuth protests, almost plaintive.

"So tell me!" his friend half-requests, half-pleads. It makes no sense. Sherlock doesn't fret as much over missing details on a case, for crying out loud!

"I won't!"

Sherlock takes his phone instead, and an irritated John is about to leave him alone, when a quick gesture stops him on his tracks.

The sleuth actually calls, not texts, and it's enough to make John worry. When at the second ring someone answers, and Sherlock replies softly, "Mycroft," the doctor knows it's serious and almost shivers. Sherlock calling Mycroft willingly? The older brother is informed of the 'emergence', with a lot of, "It's unfair!" and angry, "Why are _you _okay?", and John expects him to offer a firm lecture over what constitutes an actual emergency, but Sherlock's face is not of one being reprimanded.

"Will you tell John?" the detective asks, before handing over the phone.

"I'm sure you reckon Sherlock is being over-dramatic as usual, but he has an actual reason for his distress," Mycroft assures him calmly, which is very distressing to John in turn, but he tries to keep it under control.

"What?"

"What do you know of EOFAD, doctor?" Mycroft counters.

"I might know something if you give me the non-shortened version; now I can only say a bullet doesn't cause it," he replies.

"I'd be very surprised if a bullet triggered an autosomal dominant disease like Early-Onset Familial Alzheimer, Dr. Watson. This ailment tormented our father, unfortunately...so you see why Sherlock and I might be oversensitive about our memory's failures, even the most insignificant," comes the cold, collected voice over the line.

"Dominant means he'd be sick even if half his genes didn't carry the defect responsible for it. With enough luck, you both could not have inherited those. Have you been tested for that?" John asks, in full doctor mode.

"It's bad enough being a ticking bomb, John...neither of us dared to know if we would really go off someday. Sherlock's dislike of hospitals didn't help."

"Well, that's silly; you both should. Or at the very least Sherlock, because having a panic attack over the tiniest memory slip isn't healthy," John remarks. It could give them peace; or not, but they'd know to prepare for when it happens.

"I'm not going to," the detective grumbles.

"Thank you Mycroft, I'll let you know," the doctor says before hanging up. "I'll come with you, Sherlock, come on."

"And hold my hand? I'm not a child, John!" the sleuth snarls.

"You could be healthy, Sherlock!" John shouts. He'll regret that.


	3. Chapter 3

_Disclaimer: nothing mine but the angst_

_A.N. I am aware that in BE a doctor specialized in a field is called a consultant, but I abide by the "Thou shalt have no other consultants" rule to avoid getting confused._

Chapter 2

It takes three days to finally bring Sherlock to get tested, and only because he's sure he already knows the results and John needs to stop deluding himself too. The headache is not permanent anymore, but it's worse now – his brain feels filled with cotton around the edges, and random bytes of knowledge keep disappearing.

The detective hates it, but his usual facade is gone. John is at his side – obviously – and Sherlock's taunt has turned out true. He's simply giving out a biological sample, but he's trembling, terrified of the anticipated answer, and John is too _steadying_ for the detectiveto let go of him. They're out of the place as soon as they can.

It takes another couple of days to check the mutations of the three known genes responsible for EOFAD (presenilin 1 and 2 and amyloid precursor protein), and by then John is inclined to share Sherlock's conviction. He's used to Sherlock deleting things, but when the detective complains about having forgotten _three _types of tobacco ash, even, it becomes obvious this is serious.

Then the results come, and they're scary. Not because Sherlock has early-onset Alzheimer. Because he_ doesn't_, he should be fine, but his mind palace is still crumbling from the inside. The working diagnosis (just to put a name to what's happening) becomes early-onset dementia. That's not a disease, though, it's a symptom. And a symptom of too many things to name them all, from brain tumor to Creutzfeldt-Jakob (mad cow) disease to neuroacanthocytosis (whose name looks like it should belong in an art history book) to fatal familial insomnia (maybe that's it?) and so on. And on. And on.

The specialist whose services Mycroft offers – supposedly a luminary – clearly has no idea about what's happening, either. They see him a little later, and he suggests to keep Sherlock in hospital to run a full battery of tests on him. The detective snarls and almost runs, and it's only John who allows them to compromise. Sherlock will agree to the tests, but he won't be held in-between. John promises to make personally sure that the sleuth will be present for all the exams, which he would do anyway. The good doctor understands that it's to make things easier, simpler, but he still fails to see how having someone in a sterile environment might help with either memory or brain. Nothing in hospital to help jog them.

Despite his distaste for hospitals and doctors (with one very specific exception), Sherlock is very docile anytime the prospect of a new exam comes up. He lets himself be scanned, prodded, pricked, gives samples of anything and loses enough blood that way to probably risk going anemic. Everyone is relieved, of course. John too, obviously. Still, his friend can't help pondering how upset the detective must be to be this...subdued.

Sherlock thought he knew what terror was like. He thought he had it contained, inside the bolted room in his mind palace's dungeon. But that was laced with a quiet form of despair, he realizes now; the still figure of his dad, eyes vacant, looming like a ominous prophecy. There was awareness there. Of the illness, its symptoms, its development. He loathed, he feared, but he knew.

This...this unmotivated (until now) self-destruction leaves him feeling lost. The end result will be the same – all the evidence points to that; his very identity shattered by some unknown power like so much rubidium, no matter how hard he tries to hold onto it. But he has no idea about how quickly that will happen, or what is going to desert him next, so the horror of the expected finish line resonates with the anguish of incertitude, spawning a panic that requires all his strength not to break apart at any given moment and leaves him no spare energy to fight against medical personnel.

Even if he should. Oh, he should. With each test that comes back clear, the doctors (because of course, Mycroft and John aren't content to drag him to only one useless bastard) are more and more baffled, and slowly but surely running out of options. To cover their own idiocy (honestly, Sherlock would like to conduct a few of the analyses himself, if his problem didn't stop him in the first place) they start wondering if this might be a psychological problem instead...or a feint. It's after the Fall, and even with his public rehabilitation, doubts will forever linger. The fact that some days bring more clarity – and that they show no discernible pattern (not discernible to the doctors, anyway) – doesn't help.

Skepticism doesn't touch John though, never him. His friend, his undeserved anchor. John knows that Sherlock would rather chop off a few of his own limbs than hold a pretense like this, and is intimate enough with psychological distress taking physical form to recognize that whatever lies deep inside his friend's subconscious is still inherently Sherlock, and would not try to destroy him in such a way. And it would never ever take away music from Sherlock, since it's the only way all those repressed urges had to express themselves until now. A bit of common sense, really. If only everyone had it.

_Chemical P.S. FYI: I picked rubidium because in the Mohs scale of mineral hardness it's around 0.2/0.3 (keep in mind talc is 1; rubidium should shatter under a particularly harsh glare), then I learned a lot of fun facts that made it a Sherlockian element. Rubidium (symbol Rb, atomic number 37) is a silvery-white, highly reactive element of the alkali metal group. Be__cause of its large ionic radius, it's one of the 'incompatible elements'. __It has been reported to ignite spontaneously in the air, shows a __purple__color in the flame test, and refuses to form an alloy with lithium (no way he'd agree with something that slowed down the brain). Its natural isotope __87__Rb is radioactive__, and has a half-life of 48.8×10__9 __years, which is more than three times the actual age of the universe (aiming to outlive God? XD). Aaand...__it accumulates more in brain tumors than normal brain tissue, so can be used to locate and image brain tumors. __With the hypotheses in the air, could I not mention it in this fic? _


	4. Chapter 4

_Disclaimer: nothing mine. And I hate repeating it. _

Chapter 3

Sherlock's condition progresses way more quickly than his father's. The fog in his mind's outskirts invades the rest of his mind palace, and retrieving almost any knowledge at all (what hasn't disappeared yet, at least) requires a fight. He has scant strength, and it's so very easier to let the matter – any matter – drop. It's infinitely frustrating too, of course. But John is always there, to help, to soothe. To offer what Sherlock isn't even aware of needing yet. Not that he needs much, because his activities are sorely restricted by his...situation. He should be bored to death, but his surviving thoughts are too full of worry for boredom to be an issue. The second biggest concern, just after _what's happening to me?_, is of course about his flatmate. Didn't John use to go away sometimes? _Will he leave? _In the end, it doesn't matter. John is by his side right now, and that's enough. The few times Sherlock can't keep his gaze on him, usually because his chronic insomnia keeps him conscious – or what passes for it these days – when John's body requires him to sleep, the detective can't breathe. No John is not good. More than once he's gotten out of bed (John makes him sleep mostly on his previously unused bed now) to stumble around the flat in a frantic search for his doctor.

This usually wakes John up, but he doesn't get angry. He almost never gets angry at Sherlock these days, which is a definite plus. The only one in this wretched circumstance. Honestly, the doctor would start sleeping on a cot on Sherlock's room, or the sofa, if not for his nightmares and the fact that before sleep is the only time he allows himself to be overcome by the stress and sheer agony of seeing his best friend like this. Neither is something Sherlock needs to overhear.

Even in his muddled state, it nags at Sherlock that he's not repaying John in any way for his care. He used to, didn't he? He wasn't boring, at least. If he becomes dull, John will surely go away, won't he? That's not good. Very much not good. He needs to do something. He's not clever now, though, so what can he do? His only talent has melted away. He's not himself anymore. He's barely a human being (shouldn't intelligence set humanity apart from the rest?).Well, if he isn't...

The soft mewl from the stretched figure startles John out of his book. "Sherlock? You okay?"

The dark head nods, and his friend lets out another mewl, with an added vibrato effect.

"So are you a cat now?" the doctor queries, vaguely amused.

Another nod. He can be a pet at least. John likes animals, so it's a safe bet.

The doctor wonders for a moment if this is a new symptom; if he should be worried. If it is a sign that _it is_ a mental disorder that's doing this to Sherlock. But his flatmate has always been prone to weird, apparently arbitrary behaviours. Maybe he's just bored. He can't exactly occupy himself with his usual hobbies after all. A little role-play can't hurt.

John smiles his baffled, indulgent smile, the 'I have no idea what's going on in your head but I'm willing to come along for the ride' one. Sherlock has missed that smile dearly. Perhaps not consciously, but seeing it now makes him half-giddy. He knew it was a good idea.

He curls up on the couch, freeing a space for John to sit in, and his friend complies with the wordless request. Sherlock moves a bit, nuzzling against John's side, letting out another sharp mewl.

John shakes his head a bit at his pushy flatmate, then chuckles fondly. Sherlock has always been much like a cat, no wonder Molly likes him so much. You have to keep him fed and watered, he'll ask for attention when you're too tired and/or busy to give it and hiss if you try to disturb him at all other times. Yep, a cat. The doctor's left hand instinctively finds his way to the dark curls, infinitely gentle. If only he could absorb Sherlock's problem just like this, take it away – even if he had to suffer himsef – he would. He'd be happy to, really.

Sherlock's hair is awfully sensitive, and he eyes the hand a bit suspiciously, but he has to be a good pet for John to want to stay. He's happily surprised by the tenderness in his friend's touch. A tiny sigh of pleasure leaves his lips, then he remembers his role and starts quietly purring. A quick glance to John shows a surprised, but definitely happy smile. Sherlock lets his eyes fall closed and enjoys the moment.

_A.N. I don't know how Catlock found his way in this, and I apologize about ruining it with so much angst. (You'll see.) I love it. __I love cats. If at all possible, I want to__ be reborn as a cat, but no one knows or wants to tell me exactly which sins I have to commit to do so . Double update today to make up for it!_


	5. Chapter 5

_Disclaimer: Nothing is mine. Obviously. _

Chapter 4

Sometimes, a day will be better – clinically speaking. The fog clears almost completely, lingering at the edges just enough to let Sherlock know he's not miraculously healed yet. He should be happy. Ecstatic even. Instead, he's never more miserable. When he can think, really _think _clearly, the only topics he obsesses over are exactly how much he's lost now and how low he's sunk.

This, in turn, makes any relief the good doctor might be feeling evaporate. Seeing Sherlock in a daze hurts, but seeing him disconsolate like this, and being unable to offer any comfort, tears John apart. Platitudes have never worked on Sherlock, and there is no fact he can offer that would make it any better. They don't even bloody know what it is yet, much less how to heal him. This when John's allowed to be by the detective's side at all. When Sherlock is _better _(so to speak), more often than not he avoids his friend. John wonders if, somewhere in that brain of his, Sherlock has come to associate him with his own spells of confusion. Being stopped from caring is a form of torture, but he won't force his presence on Sherlock. That would surely only add to the damage.

John's hypothesis is way off, as always. It's not like Sherlock doesn't want him around. When he's clear headed, he's just too ashamed to bear John's knowing gaze. He's turning into something worse than Anderson, and for some absurd reason (Hippocratic oath?) John still stays. He shouldn't. John needs excitement, adrenaline, not a...a burden. He needs to get away from Sherlock before his life is swallowed entirely (and aren't they too close to that already?) by a not-consultant-anymore sized leech. Can't John _see_? If he shies away from his friend it's only to give him at least a bit of freedom.

When a 'good day' finally comes, after the cat impersonation, just remembering it is enough to make Sherlock physically sick. He manages to run to the bathroom before his stomach starts emptying itself. It's way too full. Doesn't John know food slows him down?_ Not like you can get any slower without going brain dead_, he snarls to himself.

The doctor is with him, of course. John might respect his need of solitude, but can't be kept from doctoring. Even when he can't do much besides keeping Sherlock's curls out of the way when he's heaving. Or comforting him with a light touch. Sherlock, ungrateful as always, glares – weakly – when the contact becomes too close to the petting _he_'d asked for, in his cat-self.

"'M not...pet," he manages to get out.

"Of course you aren't. I didn't want to upset you. Just to help," the doctor agrees, changing the movement and rhythm of his hands slightly. He didn't mean to imply anything of the sort. But lately Sherlock had enjoyed the feline role-play and his hands, needing to soothe, acted without much input from his brain.

John looks taken aback at his protest, even if he behaves accordingly, and it confirms what Sherlock already knows. This needs to stop. He can't keep John. He needs to chase him away before it's too late. Before he does turn into a pet – less than a pet – and accepts it as a good thing, a natural thing...as _enough_. John must not be chained to this him. He mustn't see it. Not anymore at least. Because it won't stop there. He'll be John's pet, than John's doll, get off his transport and still require more and more care. He doesn't want that. John's life shouldn't turn around Sherlock's needs when he will have nothing to offer. Sherlock is not going to ruin his only friend's existence.

"It was nothing," he says, if a bit weakly, when he's finally done.

His friend doesn't object, but looks him over with his sharp professional look, trying to determine what might have prompted this.

Sherlock goes back to the sitting room and flops dejectedly on the sofa. Here goes nothing. He needs to break free from his John-dependence.

"John..." he calls. Then the brain-mouth connection clearly gets scrambled, because instead of ' go away' or something like that, he breathes, "don't leave me."

His friend looks upset, and Sherlock wants to explain, blame it all on his illness, tell him that of course John can leave, that he_ should_, but he never manages to do so.

"What did I ever do to make you think that I would?" John asks, still looking positively wounded.

"Nothing," he whispers hurriedly "but we did, Mycroft and I, and I'm...". He swallows the end of that sentence, the bravery of confronting the problem – of driving John away – already drained out of him.

"Sick?" his friend ends for him, matter-of-factly. "You're human, Sherlock, and we're working on it. We'll understand your problem, I promise." Even if he can't. "Slower? I've stuck by you through bio-hazards and you deceiving me – as necessary as it was. I'm not about to leave because life is quieter. And I'm sure neither of you would have left your dad if you weren't sure he was properly cared for. _I_'m certainly not entrusting your care to anyone else."

"I'm useless, John," Sherlock corrects him. He needs to, however much he doesn't like it. John's unwavering loyalty brought back Sherlock's resolve to free him. He doesn't deserve his blogger. "You'd be better off without me. I've seen how taking care of someone like me overburdens people. You _should _run. And your conviction lacks any proof."

"But he _is _cared for, isn't he?" the doctor quips. "I don't need proof, Sherlock. I know you. As for Mycroft – let's say I've got a strong hunch about him." He swallows once, before continuing, "The rest it's all absurd. I'm made of stronger stuff than you think, thank you very much. You can't overburden me, Sherlock. Not even burden, I swear. And I can't imagine a universe where I'm better without you. Not the one where you're still using, not the one where your dad did transmit you EOFAD and we met only after you got ill, not the one where you're a bloody Cyberman. You have to believe that!"

"Why didn't you choose creative writing, instead of blogging about what actually happened? You have imagination enough," the brunette replies, instead of arguing his point further (even if he knows he's right). John will have to acknowledge it soon enough. He'll leave then – later than he should have, sooner than Sherlock can bear, unless the former detective will be lucid enough to know why it needs to happen. Improbable. For now, though, it's the first compliment he's ever paid to his friend's writing skills, and his stupefied face is quite endearing.

"Today must be worse than we thought, if you're liking my scribbles," the doctor jokes. He knows exactly how good today is; Sherlock's been miserable enough.

"I like them, John," the detective admits. "They're just wrong for the subject."

"Now I'm sure you haven't been possessed or body-snatched by an alien." John grins, even faced with his friend's puzzled look. He can almost pretend things are normal for a second. It's not like usual Sherlock would get sci-fi references anyway.


	6. Chapter 6

_Disclaimer: Do you think anything's mine? Still? Really? Your brain needs checking too. _

_A.N. TRIGGER warning: suicidal thoughts _

Chapter 5

About a month passed, and they're still no closer to at least knowing. Oh, they know a lot of things Sherlock's illness is _not_, but nothing that could give an hint on how to heal him, or at least to manage this the best way possible. His brain is cannibalizing itself, they're starting to think. Whatever that is supposed to mean. Most of the time, he's very quiet, very compliant with whatever John asks of him. Which is of course completely heart-breaking. They're no meant to work like that.

Today is a good day again, though. Sherlock takes stock of his losses. It should be impossible, but for him it isn't. When he deletes things, he doesn't just throw away the notions. He defragments the hard drive, and renovates the mind palace accordingly. Wallpaper is changed, shelves erased. Now empty furniture haunts many of the rooms, wallpaper that held relevant information looks like murky gray mud.

He wanders inside the palace, and what he finds terrifies him. A room completely voided of any hint of its previous load of knowledge. Which would be bad enough, but the failed renovation lets him know what he's lost. The room has a bed. The only rooms with a bed are the ones in which he kept information about people. This is not one of the rooms for the guests (aka, people involved in a case). It's too big for that, it must have contained plenty of data. What's more, the room is easily accessible. He wouldn't bother with that if he hadn't reason to visit it often. He has just forgotten someone. A whole someone. Someone important to him.

Crushed by this, he has not left his room (in the real world) at all today. At midday, John knocks gently and then comes in (so quietly, not wanting to disturb if Sherlock is somehow asleep) with a cup of tea. It's nothing more than an excuse to check on him, but it will still appease Sherlock if he's upset (hopefully).

Sherlock needs much more than a cup of tea. After such a realization, the doctor finds him in a full-fledged panic attack. Seeing the trembling, panting form, John does not drop the mug. He sets it aside on the bedside; stimulants, even mild, will not help Sherlock now. He hugs his friend, gently, asking what's wrong, pleading with him to breathe in tandem with the forcibly calm doctor. For awhile nothing happens, as if John's presence went unnoticed. Still, slowly Sherlock stops hyperventilating. The embrace is even returned, with all the considerable strength his wiry appearance conceals. John might end up having bruises from being so desperately held, but he's not about to complain. Now, if only Sherlock told him what's got him like this...

"Can I help?" he finally asks.

"Not really; not unless you have a treatment." That is a low blow, because of course if John knew what to do he'd be already doing it. He's not Mycroft. The last time Sherlock was somehow lucid, he's been wondering. It's true that his brother is a very busy man, and that Mycroft has never taken a strong interest in science. But Sherlock maintains that if their places would be reversed he would have managed to understand what the problem was, if nothing else. That Mycroft has not, by now, makes him doubt his brother might like him better like this. He won't cause turmoil that needs to be dealt with, and can easily be kept hidden. As if he never existed. It ought to be Mycroft's dream come true.

He's always known, from the start, how it would end, but Sherlock had waited – hoped (so _stupid_) – for a cure, some sort of remedy, a way out before it went too far. There won't be one. It's clearly reached too deep already, he's going to be a...a lump of flesh soon enough. Completely oblivious and then, inevitably, forgotten and forsaken in return (if he's lucky; if John doesn't cling to what won't be there anymore). Nothing of what he guards in the mind palace – nothing that makes him him – will be safe. And that is simply unacceptable. The only way out...

"If you really want to help, kill me," he whispers against his friend's shoulder. He can still die when he has a shred of his own self to hold onto; not a broken doll.

"Don't even joke about that," John croaks out, tightening his hold. "Ever."

"Please, John," Sherlock entreats, sounding so honestly _eager_ and heartbroken that his friend would hurry to comply with anything else.

"Stop it, Sherlock. Just stop. Why are you saying this?" It's almost a wail.

"It's better for everyone, really. I've forgotten someone, John. Completely. I can feel the hole he or she left behind, and it's big. I've forgotten someone meaningful. Nothing's safe. I know how it is. I'll end up being here without being here, get off my transport, alive but still missing. I don't want you to see when you'll be deleted, John. I don't want you to stick to me when I can't realize it. And it's going to be soon. If I'm dead at least you can move on," he replies, forlorn but determined, trying to disengage himself.

John's sharp, bitter laugh stills him. "Yeah, because that went so well. Look, I don't know if you've forgotten – might be better for you if you have, actually. But I've believed you dead once already, and trust me. I'm shit at moving on. I don't care if I get deleted, Sherlock. I don't care if you don't remember your own name. Until you're alive, I can still hope. And even if I can't hope, I can make do with what I have. You're too precious to give up," the doctor confesses, his voice progressively softening, but his hands firm – he's not letting Sherlock go.

"But it won't be me. It'll be just...flesh. And I really, really would rather be dead than forget you, John. I don't want to exist if I'm empty. If I forget that at least one person in the world stood _willingly _by me" his friend whispers. He'd give up the rest if he could keep his knowledge of John, and regard it as a good barter. He can't. He's going to disappear, crumble from the inside, and the prospect of seeing John and not knowing him, losing all John is (home, safe, good) is unbearable. As much as – or more, if he's really honest with himslef – than every other implication of becoming a empty-headed puppet.

Sherlock's admission slices through the doctor like a scalpel. Like every other time his best friend's absolute loneliness flashed into the light. The urge to spew random superlatives as antidote usually follows. Not this time. He needs something better.

"I know we have no way to be sure, but you have a rough idea of how much you've lost and how quick, so...do you think we have another couple weeks? Before you lose what you absolutely don't want to lose? Because I'd like to cut you a deal."

"A week, John. Not more. If I'm lucky, perhaps ten days. If the rates don't slow down, I'll be gone by that time." And then, because curiosity will stay with Sherlock until his last brain cell fizzes out, he adds, "What deal?"

John grimaces at how short that period is, but he's not backing down. "I'm finding you a hope. A working hypothesis, a miracle treatment...I don't know. But I'm finding it in this week you've allotted me, and no matter how you feel, you have to promise me you'll hang on. When time's up...if I have nothing to offer, and you haven't changed opinion, I'll set you free. On one condition, mind. You agree to let me follow," he says, very slowly and deliberately.

It's the next best thing. He'd like to keep Sherlock forever, if he could (well, not forever; they're humans). But John understands that what looms on the horizon is simply inadmissible for Mr. "Anything-but-my-brain-is-only-transport". Rather than having to fight him to keep him alive every time Sherlock will be half-lucid, the doctor's willing to let his friend lead the way as usual. What he absolutely won't stand for is letting Sherlock go a millisecond before everything is truly, irrecoverably lost.

"But John...you are..." Sherlock starts to object, his head leaving his friend's shoulder to look him right in the eyes, his own gaze almost as sharp as before.

"If you say fine or okay or something along these lines I might scream," John warns quietly. "I've been broken since before I met you. And I've had enough of grief for a lifetime, thank you very much. I'm not going through any of that again. Much less killing you myself and living with it. I'm just giving you the full picture so you can choose. So? Do you agree to that?"

"Oh fine!" Sherlock grumbles. Since the start of this he couldn't do anything but go along with John after all. He doesn't want to involve John in his ruin, but he can't outsmart him anymore and persuading him when he's this stubborn has always been impossible. He'll have to ponder if keeping John alive, however tied to him (if John isn't smart enough to run, as it seems), is worth surviving when his identity has been stripped from him. He used to think nothing was worth that half-life, but...John. Dying. Because of him. Unacceptable, too. So? He needs to think (and soon he won't be able to anymore).

For all intent and purposes, he looks ready to a good sulk, and John leaves him to it. He has something to do after all. He hasn't updated the blog since before Cardiff – half a lifetime ago – and he didn't think he'll ever make known what happened. But he has a week to save Sherlock's life, and the doctors Mycroft recommended weren't useful at all. So he writes this up (with all the medical details it requires), knowing he's betraying patient-doctor confidentiality, that Sherlock will hate him if he realizes, that Mycroft will flay him, kill him, drop his body in the Bermuda triangle...and then fish it out to start again. But he's desperate, and honestly, if a cousin of a brother-in-law of a friend of a follower of his blog knows of any illness they haven't yet thought of, or knows someone who recovered his brain functions after being treated by a bloody witch doctor, John needs to be informed. He needs to save Sherlock, even if it kills him.


	7. Chapter 7

_Disclaimer: I don't own a thing. _

_A.N. I've just discovered this doesn't happen in BBC!Universe, but in the Fixed!Torchwood AU where Jack Harkness is the only one allowed to ever die. And I used my godly author powers to make time even more wibbly wobbly than it usually is and have Post-Reichenbach and Torchwood mid-season-2 in the same time frame. I might or might not have opened the Rift for this. Send me the bill. XD _

Chapter 6

It's the following morning, and before John can even check his blog, results are at the door. He's barely out of bed – still hasn't managed to drink his first cup of the day – when the doorbell rings very purposefully. When he opens, two people barge in; a cute Japanese girl with a big bag and a young, arrogant-looking man who wears a white coat. Someone else Mycroft sent? Or a result of his appeal?

"Dr. Owen Harper, Toshiko Sato, from the Torchwood Research Institute," the young man introduces them. John has never heard of it, but he's not exactly updated on all the research centers in UK.

"Dr. John Watson," he greets back, just so the man knows he can't fool him. Even if the other probably knows already.

"We read your blog, and we have a strong suspicion about what the cause of your friend's problem might be," Harper states matter of factly.

Before John can reply or demand more information, the girl adds, "You've been to Cardiff before this started, right? Your friend has been caught by CCTV on the site of a...contamination of sort."

Cardiff feels something that happened in a different existence, and John wonders why he sometimes lets Sherlock run around by himself at all. Contaminated places, really?

"Contaminated by what?" he asks quietly.

"Look, can we see the patient? He has the right to know too," Dr. Harper says, waving his question away. It might just mean not wanting to repeat it all, but to John it feels like he's clearly dodging the issue. More than a bit not good.

"Of course," John agrees anyway, because the other doctor has a point. He goes to fetch Sherlock in his room. He's awake, but confused again, and the idea that he didn't want to confront the strangers that just invaded his home makes John's heart ache. But there's some sort of hope these people might bring, so he has no qualms asking his friend to face them or bribing him with tea to come after the examination.

The moment Sherlock is with them, Miss Sato opens her bag and takes out some sort of machinery, much like a digital camcorder, but with the biggest screen to check what you're recording John has ever seen.

"A month in, uh? It's a bit soon, but from the symptoms we know of I suppose it would show as a tumor already," Harper remarks off-handedly, after scarcely a look at Sherlock.

"It's not a brain tumor, none of the markers showed up," John objects sharply. That's their idea? Really? He's written very clearly what this isn't. And if Sherlock weren't ill he'd have realized John's betrayal of his privacy from that sentence alone.

"I said show as. I know it's not. It's a parasite," the arrogant bastard announces.

"Wait...that can't be...a parasite big enough to show up as a tumor...it doesn't exist," John objects. Surely nothing that big could take residence into someone's brain, could it? It would be a monster.

"Why don't we have a look?" the Japanese woman asks, her voice soft and utterly sensible. "Sit down, please. I promise it won't hurt," she suggests, smiling reassuringly to Sherlock, who just stood there, following the exchange. His eyes still turn automatically to John, who nods, because the machine doesn't look harmful, and what damage can one more scan do? The detective takes a seat on the sofa, without another word.

She regulates it, and John, looking at the screen, is surprised when he sees first the bones of the skull, in 3D. She's still tuning, though, and John can't contain the half-scream at what comes next. It's Sherlock's brain, 3D and full color, grey, blue and red of capillaries, but that's not all. There is the crossbred of a starfish and a sea anemone – at least it looks like that – it's a vibrant red, and it's holding onto Sherlock's brain like a patella to its rock. Its cilia are fluttering, and John gets the totally irrational feeling that the thing is snarling at them.

"What?" Sherlock inquires quickly, turning to check on his blogger.

"As I said, a parasite," Harper states. John averts his eyes from the...thing, breathes, tries to send a reassuring look to Sherlock (probably failing miserably, because _what was that?_) and asks,"You didn't bred it, did you?". It wouldn't be the first mad scientist they met.

A veritable storm cloud covers Harper's face, and he replies through gritted teeth, "Of course we didn't. Your friend isn't the youngest case of dementia recorded; that dubious honour goes to my fiancée, and it's in her brain I met my first." Glanced at it, more like, because he still had no clearance for that. It's true that Katie's development was a bit different, but many variables might affect it. He doesn't know the bastards half as well as he'd like.

John's quiet "I'm sorry," sounds together with Sherlock's "What happened to her?".

"She died," he admits with a grimace.

"Acceptable," the detective murmurs, eyes closing. Only to be immediately scolded by twin "No it's not!" from both doctors in attendance.

"What do we do?" John asks his colleague, turning to him as towards a superior officer. This man has to have a treatment, a suggestion...a plan. He's not come with the right attitude for a doctor who's giving you the diagnosis and the 'we are very sorry, there's nothing we could possibly do' speech.

"You could contact a brain surgeon, but they aren't really trained to work with things wriggling around up there. I'm not sure even the best of them wouldn't slip, and that won't be pretty. I' d do this myself, but with the traditional means I can't promise much. Luckily, we're a research center, so we got _this_," he replies, fishing around for something in his partner's bag. Something not much different from an old-model mobile phone with a couple of screws on the side, actually. He presents it with a very smug smirk.

"And that is supposed to be?" John queries, while the woman remarks sharply, "That has worked a grand total of two times, Owen. Are you really sure?".

"This, mate, is my singularity scalpel. Guaranteed for removal of anything from anywhere without even brushing the rest. Well, when I say guaranteed... Don't jinx me, Tosh!" he starts to brag, but halfway through all that arrogance slips away.

"What's the absolute worst that could happen?" Sherlock's deep voice rumbles.

"If you're lucky I won't hit you at all. Probably damage the stairs." Owen shrugs.

"I said the worst," the detective insists, voice clipped and body rigid.

"Honestly? I have no idea. Maybe take away an hemisphere?"

John's horrified, "What?" is the only reaction to that. Sherlock is still processing the information or keeping himself in check.

"You don't need to worry, though. It won't happen. I won't lose against _that_." There's steel in Owen's voice.

"And it might leave absolutely no damage behind," Sherlock ponders softly.

"Yeah."

"Do it," the detective orders.

"Sherlock! No!" John pleads, waving wildly around. "His own partner doesn't trust him, and you want to play guinea pig?! Really?"

"It's my brain, and I'm giving consent," Sherlock grits out, "or do you want power of attorney, John?".

That stalls John. He could say yes – should say yes, but it would break Sherlock. And John would never get it anyway. He'd have to call Mycroft, and explain. And get killed by the older Holmes. That can come later. So he does the only thing he can do. He glares at Harper, with his gadgets and his arrogance, willing his own eyes to convey how Sherlock won't be dying alone if the researcher botches this up.

Owen only smirks back, declaring, "Lets get this fucker out."

And he does. The thing is on their floor (perhaps not the worst thing ever there), wriggling, grasping at nothing, and then quickly wilting. Sherlock looks at it, with his formerly usual laser gaze, and when Tosh takes it with pliers and seals it in a lead container he looks decidedly dejected.

"Sorry. You don't get to experiment on that," Owen apologizes, smiling. "Do we have anything to toast to our success with? Even tea?" Because, let's face it, alcohol is not for this soon in the day. Not if you aren't Harriet.

"Of course, I'll get to it," John agrees, moving to put the kettle on. He'd have offered already if his mind weren't very much otherwise occupied. Still trying to wrap itself around what he's seen and simultaneously trying to delete the image of that creature squirming around in Sherlock's skull and eating from his brain. Too bad his friend is the only one who knows that trick.

"John, no!" Sherlock barks sharply.

"What?" John replies, suddenly halting.

"You said that thing shouldn't exist. It doesn't matter if they've bred it or not. I'm sure we have not enough clearance to know of its existence. They'll try to drug us, make us unreliable witnesses if we're even supposed to remember it. So don't play into their hands," the detective rants.

Owen should deny it, really, but he doesn't. He says, "Whoa, you are that good!" instead. John glares at him. Even if you've just saved someone, drugging his tea is firmly on the Not Good list.

"The last thing they need is to forget more," Tosh agrees, "especially forget how he's healed. It'll drive them crazy. If we just tell Dr. Watson the cover story, he'll agree to spread it, right?" – and she offers a sweet smile.

"But, Tosh!" Owen protests while John nods energetically. Really, drugging them because they don't think he can keep his mouth shut? Are they idiots?

"Jack finds him hot," Tosh says, nodding towards the detective, "and they're cute together. I'm sure he won't mind," and she grins.

"Hot? Is that what you need to get clearance?" Sherlock remarks scathingly, raising a eyebrow in shock.

"Among other things," Owen sighs. Much like John himself when he's confronted with his flatmate's more annoying quirks.

"If you do tell me the cover story, we can all have good, not drugged tea before you need to be on your way," John steps in, before Sherlock can start a fight first thing after being in complete control of his mind again (even if he's right). The detective must be still worn out from the illness and unconventional surgery, because he doesn't press further. So that's exactly what happens.


	8. Chapter 8

_Disclaimer: Nothing mine. Honestly._

_A.N. I mention in a perhaps too light way Sanfilippo Syndrome. I apologize, but I thought the angst in here had been quite enough. Wiki informs me that gene therapy__is under Phase I/II clinical trial in France since October 2011 (under the leadership of Paris-based biotechnology company Lysogene) and I made use of it. Let's hope it bears fruit. In this story's universe, I wanted to ensure it. _

Epilogue

"I'd better write the cover story down before I forget the details," John remarks later. "I'll keep it in the drafts until it's time to publish it."

It's not entirely a bad cover; unbelievable, and somehow medically impossible, but not more than brain parasites bigger than a fist. Late-blooming Sanfilippo Syndrome. Or, Sherlock syndrome perhaps, since he'd be the only recorded example. The Sanfilippo Syndrome (another genetic disorder) affects children, so it looks logical that they wouldn't think of it. And while some symptoms definitely don't fit (stiff joints? Incomplete acquisition of speech? Really?), a few (temper tantrums, hyperactivity, destructiveness, aggressive behaviour, sleep disturbance) could make plausible an ill but unrecognized Sherlock for a while already before the condition ruined his life. According to Miss Sato's story, Sherlock would have agreed to be guinea pig for a gene therapy currently on trial. Obviously it would have worked for his very peculiar situation. Dr. Harper said that one such trial is really ongoing and guaranteed it will end up giving results soon enough. They're apparently collaborating with the French labs involved. John can't divulge Sherlock's better until more time's past from his internet plea, but it's fine, since Sherlock needs time to rebuild his Mind Palace anyway.

The moment John opens his blog, he expects Sherlock (who's loitering around, searching for some monographs – of which he's the author – that he was too lazy to upload on his web page) to make loudly known his displeasure. Outrage, more likely. John's betrayal deserves it. Steeling himself is useless, though. The detective doesn't comment. John would say he didn't notice, but if he's well enough to see they're trying to drug him, Sherlock is definitely well enough to discern what the blog's last post is about. The doctor has no idea what to make of this lack of reaction.

By the time he has written and saved the draft, Sherlock has finally found a monograph on different soils' characteristics and their distribution across UK and is happily reading it. John leaves him to it and sends a quick text to Mycroft. _He's healed. _The elder Holmes needs to know, even if drawing his attention is the last thing John wants.

_How? _It's the first text from either Holmes brother unsigned, but it's understandable. You don't normally get from 'we don't even know the illness' to fine, unless you went to Lourdes that is. Mycroft has every right to be shocked.

_Dr. Harper, Torchwood Research Institute. _He's setting the bloke up for a kidnapping, but their research will probably be largely funded, so he doesn't feel too guilty.

_Oh. That explains it. MH_

No, actually it doesn't, not at all, but it's not the right moment to glean information for the British Government. Actually, he better prepare for the oncoming storm, shouldn't he? So he does, going to his room and starting to pack. In three minutes, Sherlock is throwing open his door and observing him the way normal people look at car crashes. The ' this is horrible but I can't turn my eyes away' expression.

Not screaming is all the detective can do. Of course John would leave, would want to move (he's not reorganizing the room, or packing for a weekend away; he'd have told Sherlock in this last case) but _why now?_ He'll get better. Reconstructing the Mind Palace might take a few weeks, but he'll get back to his old self. They can go back to adrenaline-fueled chases...eventually. John liked that. Is he finally fed up with Sherlock? But he hasn't done anything, except getting ill that is, and if that's the problem why didn't he run before? ...It was really because of that damned Hippocratic Oath, wasn't it? Sherlock has proved himself too...frail, or weak, or something, for John to stand him anymore.

He needs to be proven right, though. As always. He needs to hear John say it. So he grits out, "Why?", while encompassing the room and John's packing with a sweeping arm.

"Anticipating," it's the infinitely frustrating reply.

"What?"

"You kicking me out? Mycroft having me removed? Whichever do you think will come first?" John answers, stopping his work and sitting on the bed, actually interested.

"Have you gone mad John? Because now is really not the time. Why would either of us plan that?" he asks, coming closer. Maybe he can stop it.

"The blog, Sherlock. I know you've seen it. That was quite a spectacular breach of confidentiality, one you didn't give consent to, and somehow I doubt Mycroft will be content with having me struck off the GMC. Off the planet would be slightly better. And he'd be right, of course. You'd be right if you didn't want to see me anymore. I was just..." the doctor confesses, because he might be many things, but he's not a coward.

"Desperate," Sherlock ends softly for him. "Look, I don't care. I _really_ don't care about who knows what, and had you asked, I would have told you. You were allowed to search for a treatment, anyway. I'm sure discussing my illness was supposed to happen. You had no time to be picky. Do you think I don't understand that? And it saved my life. They wouldn't have come had you not asked for help. If I were dumb enough to be inclined to feel upset over it, I would still forgive you because of that. I'll talk to Mycroft if need be, but since he hasn't appeared yet I imagine he sees things like me."

Really, John's morals are so cumbersome sometimes. Attempting to run away because he breached confidentiality? Sherlock is the king of destroying others' privacy and spilling any so-called secret. And he really, really doesn't care what people who don't count think about him. He was angry about the solar system revelation because it made him look like an idiot, but this is not being an idiot, it's being sick. The media circus can bite into it like it did with everything else concerning him, for some unexplainable reason. They'll find something else to gossip over soon enough anyway.

"Are you really not feeling...offended, betrayed or worse? You seriously won't ask me to find other accommodations right now, will you?" John queries, because he can't quite believe it. For all the attention he naturally attracts, his friend is an intensely private man, and having his illness exposed (especially the one that's just gone)...even if it worked, how can he _not _resent John?

"I can't believe you want to discuss feelings now, but yes, I wasn't lying. I had no reason to do so," Sherlock says. _Of course I'm not betrayed, John. You saved my life – again, if vicariously. And I'm not going to say thank you. _"John, the one thing you can be certain of is that I won't ask you to relocate, now or later. Leaving the flat will be your own choice or you'll still be here when you'll be Mrs. Hudson's current age and limping out of organic causes like her. So stop being an idiot and come back to the living room right now."

John should be annoyed, but he's not. He's grinning like the idiot he's been accused to be, actually. Sherlock's brain has been freed from his parasite by only a few hours and he's back to insulting other people's intelligence already. Yep. Things are definitely on the way to normal.


End file.
